The pay gap is more pronounced that that between gay people and their bisexual colleagues.

On average, gay men earn 5 percent less than straight men, and lesbians earn more than straight women.

Mize notes that, without bringing in stereotyping and discrimination, the wage gap for bisexuals is harder to explain.

“All non-heterosexual individuals face negative stereotypes and — sometimes — discrimination. However, bisexual men and women face additional stereotypes that can be particularly disadvantaging,” Mize told NBC OUT in an interview.

“One thing that has driven an increase in social acceptance of gay men and lesbian women is an increase in perceptions that they are sexual orientations someone is born with, or have no choice in. However, because bisexual men and women are romantically interested in both men and women, individuals view them as having some degree of choice to their sexual orientation. Perceptions of choice are important, because people are more likely to discriminate against a person if they believe that person has a degree of choice to their disadvantaged status,” he added.

He also notes that the stereotypes faced by bisexual men are “immature or dishonest about their sexual orientation”, but that they can “culminate into general perceptions that bisexual men and women are less competent and capable.”